/*
 probe.c - code pertaining to probing methods
 Part of Grbl

 Copyright (c) 2014-2016 Sungeun K. Jeon for Gnea Research LLC

 Grbl is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 Grbl is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.

 You should have received a copy of the GNU General Public License
 along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "probe.h"
#include <string.h>
#include "grbl.h"
#include "cpu_map.h"

// Inverts the probe pin state depending on user settings and probing cycle mode.
uint8_t probe_invert_mask;

// Probe pin initialization routine.
void probe_init()
{
    PROBE_DDR &= ~(PROBE_MASK); // Configure as input pins
#ifdef DISABLE_PROBE_PIN_PULL_UP
    PROBE_PORT &= ~(PROBE_MASK); // Normal low operation. Requires external pull-down.
#else
    PROBE_PORT |= PROBE_MASK;    // Enable internal pull-up resistors. Normal high operation.
#endif
    probe_configure_invert_mask(false); // Initialize invert mask.
}

// Called by probe_init() and the mc_probe() routines. Sets up the probe pin invert mask to
// appropriately set the pin logic according to setting for normal-high/normal-low operation
// and the probing cycle modes for toward-workpiece/away-from-workpiece.
void probe_configure_invert_mask(uint8_t is_probe_away)
{
    probe_invert_mask = 0; // Initialize as zero.
    if (bit_isfalse(settings.flags, BITFLAG_INVERT_PROBE_PIN))
    {
        probe_invert_mask ^= PROBE_MASK;
    }
    if (is_probe_away)
    {
        probe_invert_mask ^= PROBE_MASK;
    }
}

// Returns the probe pin state. Triggered = true. Called by gcode parser and probe state monitor.
uint8_t probe_get_state()
{
    return ((PROBE_PIN & PROBE_MASK) ^ probe_invert_mask);
}

// Monitors probe pin state and records the system position when detected. Called by the
// stepper ISR per ISR tick.
// NOTE: This function must be extremely efficient as to not bog down the stepper ISR.
void probe_state_monitor()
{
    if (probe_get_state())
    {
        sys_probe_state = PROBE_OFF;
        memcpy(sys_probe_position, sys_position, sizeof(sys_position));
        bit_true(sys_rt_exec_state, EXEC_MOTION_CANCEL);
    }
}
